The concept she articulated applies to all human societies throughout history. She simply articulated the social dynamics occurring in the leadup to the Civil War.
In fact, new state admissions had to be split between free and slave, to keep this symmetry.
One of the laws which did the most damage to the South was the "Navigation act of 1817." This law was passed with the support of Southern states which at the time could not see how this law would hand a monopoly over to Northeastern interests. By 1860, the coalition of Northern states could do anything they wanted and leave the South paying the bill. (The South produced 72% of the total trade with Europe, and all taxes came from trade with Europe.)
So you agree the South wanted that status quo.
Thank you.